And it probably never will. As I said before, vCenter/ESXi does not have that level of insight into how the Guest OS is managing its memory. Only thing the hypervisor knows is how much is granted to the VM (4GB), consumed (again 4GB), active (which is where I still think you're trying to make a square peg fit into a round hole with trying to associate memory consumed *within* the Guest OS to what ESXi knows is being actively used/accessed by the VM), etc.
Active memory will only show you what the hypervisor sees the VM is actively using, regardless of how much is consumed and regardless of how much the Guest OS shows is free/cached/etc.